The aryl N-methyl carbamates represent a well-known class of insecticides which are active towards parasites belonging to different orders and species.
In Nikles, U.S. Pat. No. 3,819,678, there is disclosed a class of carbamates having the general formula: ##STR1## where R.sup.1 represents a C.sub.1 -C.sub.5 alkyl, C.sub.3 -C.sub.5 alkenyl or a C.sub.3 -C.sub.5 alkinyl radical or has the same meaning as R.sup.2 ; R.sup.2 represents a C.sub.3 -C.sub.5 alkenyl radical substituted by 1 or 2 halogen atoms or a C.sub.1 -C.sub.4 alkyl radical substituted by a C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkylmercapto or nitrile group; R.sup.3 represents a hydrogen atom or a methyl radical and R.sup.4 and R.sup.5, the same or different, each represents a hydrogen or a C.sub.1 -C.sub.5 alkyl radical.
These compounds are disclosed as effective pesticides for controlling nematodes, insects and representatives of the order Acarina (acaricides). A drawback of such compounds, however, is that they possess a rather low persistence on the ground so that their insecticidal activity disappears after only a few days in the field.
Other compounds of the same class as above are disclosed in German Pat. No. 1,145,162 (known under the trade designation Aminocarb) and in U.S. Pat. No. 3,084,097 (known under the trade designation Zectran). ##STR2##
These are proposed for combatting Coleoptera, Lepidoptera and Acari. Unfortunately, Aminocarb, Zectran and related compounds are also rather toxic to mammalians, having LD50 doses of 30 mg/kg and 15 mg/kg, respectively, when administered orally to test rats.
Thus, it is an object of the present invention to provide a new class of carbamates which exert an insecticide action while exhibiting a longer persistence in the field.
It is another object of this invention to provide a new class of carbamates which has a lower toxicity to warm-blooded animals than the carbamate insecticides of the prior art.
It is a further object of this invention to provide an improved method of combatting noxious insects through the use of the novel carbamates of this invention as insecticides in the field.
These and other objects which will be apparent from the following description are achieved by the present invention.